Substrates such as the surfaces of piping, vessels of metal, glass, ceramics, and the like used in industrial processes, especially in processing hazardous and radioactive materials, or in construction or used as consumer products, are prone to develop cracks or become cracked from a variety of causes. Intergranular stress corrosion cracking and helium embrittlement are two such causes of cracking in metal substrates; welding operations and metal fatigue are two others. Furthermore, cracks in metal or other piping materials or vessel walls used for transporting or containing liquids and gasses can leak, especially if the liquid or gas within the pipe or vessel is under pressure. Glass windshields develop cracks from stones thrown by tires of other vehicles; and shifting foundations will produce cracks in masonry such as cinderblocks.
Being able to apply a small amount of a material to fill, coat or both fill and coat substrates for protection against cracking, to patch, or repair it by welding cracks that have developed, rather than replace the substrate is more economical, and, sometimes, more importantly, allows vital operations to continue until the next scheduled shutdown. It is important that such a coating or patching material stop leaks. It is also important that the coating or patching material be resistant to ionizing radiation, reasonably inert to chemical attack and generally fire retardant. Ease of application is another desirable feature of a coating and patching composite especially in an environment that is harmful to the health and safety of workers where the repairing must be done simply, quickly and/or by remote means.
Glass has long been known to accept fillers for a variety of purposes. However, use of sol gel glass with fillers as a fill, coating or patching, etc. for cracks in a substrate to stop or prevent leaks has heretofore not been known.